Depends on what rubber it is.
Nitrile rubber isn't damaged by Vaseline. Neoprene and silicone is however. Silicone rubber is also damaged by silicone grease, although that is about the only rubber that is damaged by that grease.
If you don't know what rubber the seals are made of, the safest lubricant to use is animal or vegetable fat. So a thin smear of butter, marge, lard or cooking oil will not damage the seals. Even just smear of saliva or water will probably be sufficient to get the seals to slide on.